The control of arthropod pests is extremely important in achieving high crop efficiency. Damage by arthropod pests to growing and stored agronomic crops can cause significant reduction in productivity and thereby result in increased costs to the consumer. The control of arthropod pests in forestry, greenhouse crops, ornamentals, nursery crops, stored food and fiber products, livestock, household, turf, wood products, and public and animal health is also important.
Anthranilamides (see U.S. Pat. No. 6,747,047, PCT Publications WO 2003/015519 and WO 2004/067528) and phthalic diamides (see U.S. Pat. No. 6,603,044) are recently discovered classes of carboxamide arthropodicides having activity against numerous arthropod pests of economic importance.
Typically chemical active ingredients for protecting plants, e.g., arthropodicides, are formulated as compositions (formulations) comprising the active compound(s) and inert ingredients such as carriers and adjuvants. These compositions can be applied by the user to the target pests or plants to be protected either in undiluted form or after dilution with water. Formulated compositions of plant protection products can be generally categorized as solid or liquid formulations. Liquid compositions include solutions (including emulsifiable concentrates), suspensions and emulsions (including microemulsions and/or suspoemulsions). Solid compositions include dusts, powders, granules, pellets, prills, pastilles and tablets. Each formulation type has advantages and disadvantages relative to other formulation types, and the optimal type for each application will depend upon the physical and biological characteristics of the active ingredient, and the conditions of storage and use, including pests to be controlled, plant parts or other locus to be protected, environmental conditions, etc.
The penetration and translaminar movement of arthropodicide active ingredients through the waxy leaf cuticle and epidermal cells, and their subsequent distribution in the mesophyll cells, vascular system and other tissues is particularly desirable for controlling arthropod pests that primarily obtain nourishment by extracting plant sap from the internal structures of plant parts such as leaves. Particularly noteworthy examples of such arthropod pests are piercing-sucking pests of the order Homoptera, such as members of the family Aleyrodidae (whiteflies), the family Aphidadae (aphids), the family Delphacidae (planthoppers) and the family Cicadellidae (leafhoppers). Also, penetration of arthropodicide active ingredients into propagules, including seeds, is desirable for controlling not only piercing-sucking pests but also chewing arthropod pests of the order Lepidoptera. Not only does penetration of the arthropodicide into the propagule protect the propagule, but if the arthropodicide is capable of translocation through plant vascular tissues, foliage developing from the propagule can be protected as well.
Active ingredients that are crystalline solids at room temperature can typically be easily formulated as solid compositions, because the brittle nature of crystalline solids facilitates milling operations to provide small crystals. In contrast, amorphous solids tend to smear and cake during milling. However, the attractive forces within the lattice of crystals thermodynamically impedes release of active ingredients for penetration into the waxy cuticle of a leaf or the testa of a seed.
Because carboxamide moieties are polar and support hydrogen-bonding, carboxamide arthropodicides are typically crystalline solids at room temperature. Accordingly they are generally easily formulated as solid compositions. Carboxamide arthropodicides also typically have low solubility in water. Therefore dilution in water of a solid formulation comprising a carboxamide arthropodicide typically forms a suspension of arthropodicide crystals that bind the active ingredient and thus retard absorption into plant tissues and limit efficacy in controlling sucking pests. Nevertheless, solid formulated compositions comprising a carboxamide arthropodicide active ingredient that release the active ingredient for penetration into a waxy leaf cuticle or seed testa have now been discovered.